Mesothelin is a differentiation antigen whose expression in normal human tissues is limited to mesothelial cells lining the pleura, pericardium and peritoneum. However, mesothelin is highly expressed in several human cancers, including mesotheliomas, pancreatic adenocarcinomas, ovarian cancers and lung adenocarcinomas. Mesothelin is an appropriate target for methods of disease prevention or treatment and antibodies specific for mesothelin, and vaccines comprising mesothelin are useful for prophylactic and therapeutic methods.
Classical monoclonal antibodies are currently produced in mammalian cells. Drawbacks of this method of production include the difficulty of producing and selecting appropriate clones, and the expense of culturing mammalian cells. The “next generation” of monoclonal antibodies are being engineered in E. coli. Recently, microbial expression of VH and VL domains tethered together by polypeptide linkers has created the capability of generating engineered “mini-antibodies.” These mini-bodies can be generated in E. coli in a virtually combinatorial fashion. These artificially created Fab or single chain Fv (scFv) can be linked together to form multimers, e.g., diabodies, triabodies and tetrabodies. Although they are capable of binding to antigens with almost antibody-like efficiency, these engineered, Fc deficient mini-antibodies lack the ability to interact with antigen presenting cells and are poorly immunogenic. Existing solutions to the lack of immunogenicity of engineered antibodies involve directing one of the antigen binding sites to bind directly with immune cells. This brings them in apposition, but does not result in the same MHC class I priming as would be observed for a monoclonal antibody.
Immunization with vaccines remains a cornerstone of protection against threat of disease and infection. The key difficulty in vaccine development is rapidly matching a vaccine, or antitoxin, to a specific threat. Current vaccine development strategies rely on the identification and characterization of antigens that can be targeted to successfully eradicate infection or disease. Current vaccine development strategies are time- and labor-intensive and can only commence once a threat emerges. Such strategies are also impractical for generating personalized vaccines to combat disease for which target antigens varies among individuals. Current vaccine development strategies are therefore insufficient if a new and serious threat were to emerge, for which sufficient time were not available to identify and characterize target antigens before such a threat could be contained. Current vaccine development strategies are also insufficient for generating personalized vaccines for the general population.